| Message ID | 20190306155048.12868-4-nitesh@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: Guest Free Page Hinting | expand |
On Wed, Mar 6, 2019 at 7:51 AM Nitesh Narayan Lal <nitesh@redhat.com> wrote: > > This patch enables the kernel to report the isolated pages > to the host via virtio balloon driver. > In order to do so a new virtuqeue (hinting_vq) is added to the > virtio balloon driver. As the host responds back after freeing > the pages, all the isolated pages are returned back to the buddy > via __free_one_page(). > > Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com> I ran into a few build issues due to this patch. Comments below. > --- > drivers/virtio/virtio_balloon.c | 72 ++++++++++++++++++++++++++++- > include/linux/page_hinting.h | 4 ++ > include/uapi/linux/virtio_balloon.h | 8 ++++ > virt/kvm/page_hinting.c | 18 ++++++-- > 4 files changed, 98 insertions(+), 4 deletions(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 728ecd1eea30..cfe7574b5204 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -57,13 +57,15 @@ enum virtio_balloon_vq { > VIRTIO_BALLOON_VQ_INFLATE, > VIRTIO_BALLOON_VQ_DEFLATE, > VIRTIO_BALLOON_VQ_STATS, > + VIRTIO_BALLOON_VQ_HINTING, > VIRTIO_BALLOON_VQ_FREE_PAGE, > VIRTIO_BALLOON_VQ_MAX > }; > > struct virtio_balloon { > struct virtio_device *vdev; > - struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq; > + struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq, > + *hinting_vq; > > /* Balloon's own wq for cpu-intensive work items */ > struct workqueue_struct *balloon_wq; > @@ -122,6 +124,56 @@ static struct virtio_device_id id_table[] = { > { 0 }, > }; > > +#ifdef CONFIG_KVM_FREE_PAGE_HINTING > +int virtballoon_page_hinting(struct virtio_balloon *vb, > + void *hinting_req, > + int entries) > +{ > + struct scatterlist sg; > + struct virtqueue *vq = vb->hinting_vq; > + int err; > + int unused; > + struct virtio_balloon_hint_req *hint_req; > + u64 gpaddr; > + > + hint_req = kmalloc(sizeof(struct virtio_balloon_hint_req), GFP_KERNEL); > + while (virtqueue_get_buf(vq, &unused)) > + ; > + > + gpaddr = virt_to_phys(hinting_req); > + hint_req->phys_addr = cpu_to_virtio64(vb->vdev, gpaddr); > + hint_req->count = cpu_to_virtio32(vb->vdev, entries); > + sg_init_one(&sg, hint_req, sizeof(struct virtio_balloon_hint_req)); > + err = virtqueue_add_outbuf(vq, &sg, 1, hint_req, GFP_KERNEL); > + if (!err) > + virtqueue_kick(vb->hinting_vq); > + else > + kfree(hint_req); > + return err; > +} > + > +static void hinting_ack(struct virtqueue *vq) > +{ > + int len = sizeof(struct virtio_balloon_hint_req); > + struct virtio_balloon_hint_req *hint_req = virtqueue_get_buf(vq, &len); > + void *v_addr = phys_to_virt(hint_req->phys_addr); > + > + release_buddy_pages(v_addr, hint_req->count); > + kfree(hint_req); > +} > + You use release_buddy_pages here, but never exported it in the call down below. Since this can be built as a module and I believe the page hinting can be built either into the kernel or as a seperate module shouldn't you be exporting it? > +static void enable_hinting(struct virtio_balloon *vb) > +{ > + request_hypercall = (void *)&virtballoon_page_hinting; > + balloon_ptr = vb; > +} > + > +static void disable_hinting(void) > +{ > + balloon_ptr = NULL; > +} > +#endif > + > static u32 page_to_balloon_pfn(struct page *page) > { > unsigned long pfn = page_to_pfn(page); > @@ -481,6 +533,7 @@ static int init_vqs(struct virtio_balloon *vb) > names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; > names[VIRTIO_BALLOON_VQ_STATS] = NULL; > names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; > + names[VIRTIO_BALLOON_VQ_HINTING] = NULL; > > if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { > names[VIRTIO_BALLOON_VQ_STATS] = "stats"; > @@ -492,11 +545,18 @@ static int init_vqs(struct virtio_balloon *vb) > callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; > } > > + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) { > + names[VIRTIO_BALLOON_VQ_HINTING] = "hinting_vq"; > + callbacks[VIRTIO_BALLOON_VQ_HINTING] = hinting_ack; > + } > err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, > vqs, callbacks, names, NULL, NULL); > if (err) > return err; > > + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) > + vb->hinting_vq = vqs[VIRTIO_BALLOON_VQ_HINTING]; > + > vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE]; > vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE]; > if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { > @@ -908,6 +968,11 @@ static int virtballoon_probe(struct virtio_device *vdev) > if (err) > goto out_del_balloon_wq; > } > + > +#ifdef CONFIG_KVM_FREE_PAGE_HINTING > + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) > + enable_hinting(vb); > +#endif > virtio_device_ready(vdev); > > if (towards_target(vb)) > @@ -950,6 +1015,10 @@ static void virtballoon_remove(struct virtio_device *vdev) > cancel_work_sync(&vb->update_balloon_size_work); > cancel_work_sync(&vb->update_balloon_stats_work); > > +#ifdef CONFIG_KVM_FREE_PAGE_HINTING > + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) > + disable_hinting(); > +#endif > if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { > cancel_work_sync(&vb->report_free_page_work); > destroy_workqueue(vb->balloon_wq); > @@ -1009,6 +1078,7 @@ static unsigned int features[] = { > VIRTIO_BALLOON_F_MUST_TELL_HOST, > VIRTIO_BALLOON_F_STATS_VQ, > VIRTIO_BALLOON_F_DEFLATE_ON_OOM, > + VIRTIO_BALLOON_F_HINTING, > VIRTIO_BALLOON_F_FREE_PAGE_HINT, > VIRTIO_BALLOON_F_PAGE_POISON, > }; > diff --git a/include/linux/page_hinting.h b/include/linux/page_hinting.h > index d554a2581826..a32af8851081 100644 > --- a/include/linux/page_hinting.h > +++ b/include/linux/page_hinting.h > @@ -11,6 +11,8 @@ > #define HINTING_THRESHOLD 128 > #define FREE_PAGE_HINTING_MIN_ORDER (MAX_ORDER - 1) > > +extern void *balloon_ptr; > + > void guest_free_page_enqueue(struct page *page, int order); > void guest_free_page_try_hinting(void); > extern int __isolate_free_page(struct page *page, unsigned int order); > @@ -18,3 +20,5 @@ extern void __free_one_page(struct page *page, unsigned long pfn, > struct zone *zone, unsigned int order, > int migratetype); > void release_buddy_pages(void *obj_to_free, int entries); > +extern int (*request_hypercall)(void *balloon_ptr, > + void *hinting_req, int entries); > diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h > index a1966cd7b677..a7e909d77447 100644 > --- a/include/uapi/linux/virtio_balloon.h > +++ b/include/uapi/linux/virtio_balloon.h > @@ -29,6 +29,7 @@ > #include <linux/virtio_types.h> > #include <linux/virtio_ids.h> > #include <linux/virtio_config.h> > +#include <linux/page_hinting.h> > > /* The feature bitmap for virtio balloon */ > #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */ So I am pretty sure that this isn't valid. You have a file in include/uapi/linux referencing one in include/linux. As such when the userspace headers are built off of this they cannot access the kernel include file. > @@ -36,6 +37,7 @@ > #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ > #define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */ > #define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */ > +#define VIRTIO_BALLOON_F_HINTING 5 /* Page hinting virtqueue */ > > /* Size of a PFN in the balloon interface. */ > #define VIRTIO_BALLOON_PFN_SHIFT 12 > @@ -108,4 +110,10 @@ struct virtio_balloon_stat { > __virtio64 val; > } __attribute__((packed)); > > +#ifdef CONFIG_KVM_FREE_PAGE_HINTING > +struct virtio_balloon_hint_req { > + __virtio64 phys_addr; > + __virtio64 count; > +}; > +#endif > #endif /* _LINUX_VIRTIO_BALLOON_H */ > diff --git a/virt/kvm/page_hinting.c b/virt/kvm/page_hinting.c > index 9885b372b5a9..eb0c0ddfe990 100644 > --- a/virt/kvm/page_hinting.c > +++ b/virt/kvm/page_hinting.c > @@ -31,11 +31,16 @@ struct guest_isolated_pages { > unsigned int order; > }; > > -void release_buddy_pages(void *obj_to_free, int entries) > +int (*request_hypercall)(void *balloon_ptr, void *hinting_req, int entries); > +EXPORT_SYMBOL(request_hypercall); > +void *balloon_ptr; > +EXPORT_SYMBOL(balloon_ptr); > + Why are you using a standard EXPORT_SYMBOL here instead of EXPORT_SYMBOL_GPL? It seems like these are core functions that can impact the memory allocator. It might make more sense to use EXPORT_SYMBOL_GPL. > +void release_buddy_pages(void *hinting_req, int entries) > { > int i = 0; > int mt = 0; > - struct guest_isolated_pages *isolated_pages_obj = obj_to_free; > + struct guest_isolated_pages *isolated_pages_obj = hinting_req; > > while (i < entries) { > struct page *page = pfn_to_page(isolated_pages_obj[i].pfn); See my comment above, I am pretty sure you need to be exporting this. I had to change this in order to be able to build.
On 3/6/19 4:30 PM, Alexander Duyck wrote: > On Wed, Mar 6, 2019 at 7:51 AM Nitesh Narayan Lal <nitesh@redhat.com> wrote: >> This patch enables the kernel to report the isolated pages >> to the host via virtio balloon driver. >> In order to do so a new virtuqeue (hinting_vq) is added to the >> virtio balloon driver. As the host responds back after freeing >> the pages, all the isolated pages are returned back to the buddy >> via __free_one_page(). >> >> Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com> > I ran into a few build issues due to this patch. Comments below. > >> --- >> drivers/virtio/virtio_balloon.c | 72 ++++++++++++++++++++++++++++- >> include/linux/page_hinting.h | 4 ++ >> include/uapi/linux/virtio_balloon.h | 8 ++++ >> virt/kvm/page_hinting.c | 18 ++++++-- >> 4 files changed, 98 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c >> index 728ecd1eea30..cfe7574b5204 100644 >> --- a/drivers/virtio/virtio_balloon.c >> +++ b/drivers/virtio/virtio_balloon.c >> @@ -57,13 +57,15 @@ enum virtio_balloon_vq { >> VIRTIO_BALLOON_VQ_INFLATE, >> VIRTIO_BALLOON_VQ_DEFLATE, >> VIRTIO_BALLOON_VQ_STATS, >> + VIRTIO_BALLOON_VQ_HINTING, >> VIRTIO_BALLOON_VQ_FREE_PAGE, >> VIRTIO_BALLOON_VQ_MAX >> }; >> >> struct virtio_balloon { >> struct virtio_device *vdev; >> - struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq; >> + struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq, >> + *hinting_vq; >> >> /* Balloon's own wq for cpu-intensive work items */ >> struct workqueue_struct *balloon_wq; >> @@ -122,6 +124,56 @@ static struct virtio_device_id id_table[] = { >> { 0 }, >> }; >> >> +#ifdef CONFIG_KVM_FREE_PAGE_HINTING >> +int virtballoon_page_hinting(struct virtio_balloon *vb, >> + void *hinting_req, >> + int entries) >> +{ >> + struct scatterlist sg; >> + struct virtqueue *vq = vb->hinting_vq; >> + int err; >> + int unused; >> + struct virtio_balloon_hint_req *hint_req; >> + u64 gpaddr; >> + >> + hint_req = kmalloc(sizeof(struct virtio_balloon_hint_req), GFP_KERNEL); >> + while (virtqueue_get_buf(vq, &unused)) >> + ; >> + >> + gpaddr = virt_to_phys(hinting_req); >> + hint_req->phys_addr = cpu_to_virtio64(vb->vdev, gpaddr); >> + hint_req->count = cpu_to_virtio32(vb->vdev, entries); >> + sg_init_one(&sg, hint_req, sizeof(struct virtio_balloon_hint_req)); >> + err = virtqueue_add_outbuf(vq, &sg, 1, hint_req, GFP_KERNEL); >> + if (!err) >> + virtqueue_kick(vb->hinting_vq); >> + else >> + kfree(hint_req); >> + return err; >> +} >> + >> +static void hinting_ack(struct virtqueue *vq) >> +{ >> + int len = sizeof(struct virtio_balloon_hint_req); >> + struct virtio_balloon_hint_req *hint_req = virtqueue_get_buf(vq, &len); >> + void *v_addr = phys_to_virt(hint_req->phys_addr); >> + >> + release_buddy_pages(v_addr, hint_req->count); >> + kfree(hint_req); >> +} >> + > You use release_buddy_pages here, but never exported it in the call > down below. Since this can be built as a module and I believe the page > hinting can be built either into the kernel or as a seperate module > shouldn't you be exporting it? Thanks for pointing this out. > >> +static void enable_hinting(struct virtio_balloon *vb) >> +{ >> + request_hypercall = (void *)&virtballoon_page_hinting; >> + balloon_ptr = vb; >> +} >> + >> +static void disable_hinting(void) >> +{ >> + balloon_ptr = NULL; >> +} >> +#endif >> + >> static u32 page_to_balloon_pfn(struct page *page) >> { >> unsigned long pfn = page_to_pfn(page); >> @@ -481,6 +533,7 @@ static int init_vqs(struct virtio_balloon *vb) >> names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; >> names[VIRTIO_BALLOON_VQ_STATS] = NULL; >> names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; >> + names[VIRTIO_BALLOON_VQ_HINTING] = NULL; >> >> if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { >> names[VIRTIO_BALLOON_VQ_STATS] = "stats"; >> @@ -492,11 +545,18 @@ static int init_vqs(struct virtio_balloon *vb) >> callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; >> } >> >> + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) { >> + names[VIRTIO_BALLOON_VQ_HINTING] = "hinting_vq"; >> + callbacks[VIRTIO_BALLOON_VQ_HINTING] = hinting_ack; >> + } >> err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, >> vqs, callbacks, names, NULL, NULL); >> if (err) >> return err; >> >> + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) >> + vb->hinting_vq = vqs[VIRTIO_BALLOON_VQ_HINTING]; >> + >> vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE]; >> vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE]; >> if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { >> @@ -908,6 +968,11 @@ static int virtballoon_probe(struct virtio_device *vdev) >> if (err) >> goto out_del_balloon_wq; >> } >> + >> +#ifdef CONFIG_KVM_FREE_PAGE_HINTING >> + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) >> + enable_hinting(vb); >> +#endif >> virtio_device_ready(vdev); >> >> if (towards_target(vb)) >> @@ -950,6 +1015,10 @@ static void virtballoon_remove(struct virtio_device *vdev) >> cancel_work_sync(&vb->update_balloon_size_work); >> cancel_work_sync(&vb->update_balloon_stats_work); >> >> +#ifdef CONFIG_KVM_FREE_PAGE_HINTING >> + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) >> + disable_hinting(); >> +#endif >> if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { >> cancel_work_sync(&vb->report_free_page_work); >> destroy_workqueue(vb->balloon_wq); >> @@ -1009,6 +1078,7 @@ static unsigned int features[] = { >> VIRTIO_BALLOON_F_MUST_TELL_HOST, >> VIRTIO_BALLOON_F_STATS_VQ, >> VIRTIO_BALLOON_F_DEFLATE_ON_OOM, >> + VIRTIO_BALLOON_F_HINTING, >> VIRTIO_BALLOON_F_FREE_PAGE_HINT, >> VIRTIO_BALLOON_F_PAGE_POISON, >> }; >> diff --git a/include/linux/page_hinting.h b/include/linux/page_hinting.h >> index d554a2581826..a32af8851081 100644 >> --- a/include/linux/page_hinting.h >> +++ b/include/linux/page_hinting.h >> @@ -11,6 +11,8 @@ >> #define HINTING_THRESHOLD 128 >> #define FREE_PAGE_HINTING_MIN_ORDER (MAX_ORDER - 1) >> >> +extern void *balloon_ptr; >> + >> void guest_free_page_enqueue(struct page *page, int order); >> void guest_free_page_try_hinting(void); >> extern int __isolate_free_page(struct page *page, unsigned int order); >> @@ -18,3 +20,5 @@ extern void __free_one_page(struct page *page, unsigned long pfn, >> struct zone *zone, unsigned int order, >> int migratetype); >> void release_buddy_pages(void *obj_to_free, int entries); >> +extern int (*request_hypercall)(void *balloon_ptr, >> + void *hinting_req, int entries); >> diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h >> index a1966cd7b677..a7e909d77447 100644 >> --- a/include/uapi/linux/virtio_balloon.h >> +++ b/include/uapi/linux/virtio_balloon.h >> @@ -29,6 +29,7 @@ >> #include <linux/virtio_types.h> >> #include <linux/virtio_ids.h> >> #include <linux/virtio_config.h> >> +#include <linux/page_hinting.h> >> >> /* The feature bitmap for virtio balloon */ >> #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */ > So I am pretty sure that this isn't valid. You have a file in > include/uapi/linux referencing one in include/linux. As such when the > userspace headers are built off of this they cannot access the kernel > include file. > >> @@ -36,6 +37,7 @@ >> #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ >> #define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */ >> #define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */ >> +#define VIRTIO_BALLOON_F_HINTING 5 /* Page hinting virtqueue */ >> >> /* Size of a PFN in the balloon interface. */ >> #define VIRTIO_BALLOON_PFN_SHIFT 12 >> @@ -108,4 +110,10 @@ struct virtio_balloon_stat { >> __virtio64 val; >> } __attribute__((packed)); >> >> +#ifdef CONFIG_KVM_FREE_PAGE_HINTING >> +struct virtio_balloon_hint_req { >> + __virtio64 phys_addr; >> + __virtio64 count; >> +}; >> +#endif >> #endif /* _LINUX_VIRTIO_BALLOON_H */ >> diff --git a/virt/kvm/page_hinting.c b/virt/kvm/page_hinting.c >> index 9885b372b5a9..eb0c0ddfe990 100644 >> --- a/virt/kvm/page_hinting.c >> +++ b/virt/kvm/page_hinting.c >> @@ -31,11 +31,16 @@ struct guest_isolated_pages { >> unsigned int order; >> }; >> >> -void release_buddy_pages(void *obj_to_free, int entries) >> +int (*request_hypercall)(void *balloon_ptr, void *hinting_req, int entries); >> +EXPORT_SYMBOL(request_hypercall); >> +void *balloon_ptr; >> +EXPORT_SYMBOL(balloon_ptr); >> + > Why are you using a standard EXPORT_SYMBOL here instead of > EXPORT_SYMBOL_GPL? It seems like these are core functions that can > impact the memory allocator. It might make more sense to use > EXPORT_SYMBOL_GPL. > >> +void release_buddy_pages(void *hinting_req, int entries) >> { >> int i = 0; >> int mt = 0; >> - struct guest_isolated_pages *isolated_pages_obj = obj_to_free; >> + struct guest_isolated_pages *isolated_pages_obj = hinting_req; >> >> while (i < entries) { >> struct page *page = pfn_to_page(isolated_pages_obj[i].pfn); > See my comment above, I am pretty sure you need to be exporting this. > I had to change this in order to be able to build. Thanks, I will take note and correct it in the next version.
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 728ecd1eea30..cfe7574b5204 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -57,13 +57,15 @@ enum virtio_balloon_vq { VIRTIO_BALLOON_VQ_INFLATE, VIRTIO_BALLOON_VQ_DEFLATE, VIRTIO_BALLOON_VQ_STATS, + VIRTIO_BALLOON_VQ_HINTING, VIRTIO_BALLOON_VQ_FREE_PAGE, VIRTIO_BALLOON_VQ_MAX }; struct virtio_balloon { struct virtio_device *vdev; - struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq; + struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq, + *hinting_vq; /* Balloon's own wq for cpu-intensive work items */ struct workqueue_struct *balloon_wq; @@ -122,6 +124,56 @@ static struct virtio_device_id id_table[] = { { 0 }, }; +#ifdef CONFIG_KVM_FREE_PAGE_HINTING +int virtballoon_page_hinting(struct virtio_balloon *vb, + void *hinting_req, + int entries) +{ + struct scatterlist sg; + struct virtqueue *vq = vb->hinting_vq; + int err; + int unused; + struct virtio_balloon_hint_req *hint_req; + u64 gpaddr; + + hint_req = kmalloc(sizeof(struct virtio_balloon_hint_req), GFP_KERNEL); + while (virtqueue_get_buf(vq, &unused)) + ; + + gpaddr = virt_to_phys(hinting_req); + hint_req->phys_addr = cpu_to_virtio64(vb->vdev, gpaddr); + hint_req->count = cpu_to_virtio32(vb->vdev, entries); + sg_init_one(&sg, hint_req, sizeof(struct virtio_balloon_hint_req)); + err = virtqueue_add_outbuf(vq, &sg, 1, hint_req, GFP_KERNEL); + if (!err) + virtqueue_kick(vb->hinting_vq); + else + kfree(hint_req); + return err; +} + +static void hinting_ack(struct virtqueue *vq) +{ + int len = sizeof(struct virtio_balloon_hint_req); + struct virtio_balloon_hint_req *hint_req = virtqueue_get_buf(vq, &len); + void *v_addr = phys_to_virt(hint_req->phys_addr); + + release_buddy_pages(v_addr, hint_req->count); + kfree(hint_req); +} + +static void enable_hinting(struct virtio_balloon *vb) +{ + request_hypercall = (void *)&virtballoon_page_hinting; + balloon_ptr = vb; +} + +static void disable_hinting(void) +{ + balloon_ptr = NULL; +} +#endif + static u32 page_to_balloon_pfn(struct page *page) { unsigned long pfn = page_to_pfn(page); @@ -481,6 +533,7 @@ static int init_vqs(struct virtio_balloon *vb) names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; names[VIRTIO_BALLOON_VQ_STATS] = NULL; names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; + names[VIRTIO_BALLOON_VQ_HINTING] = NULL; if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { names[VIRTIO_BALLOON_VQ_STATS] = "stats"; @@ -492,11 +545,18 @@ static int init_vqs(struct virtio_balloon *vb) callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; } + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) { + names[VIRTIO_BALLOON_VQ_HINTING] = "hinting_vq"; + callbacks[VIRTIO_BALLOON_VQ_HINTING] = hinting_ack; + } err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, vqs, callbacks, names, NULL, NULL); if (err) return err; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) + vb->hinting_vq = vqs[VIRTIO_BALLOON_VQ_HINTING]; + vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE]; vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE]; if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { @@ -908,6 +968,11 @@ static int virtballoon_probe(struct virtio_device *vdev) if (err) goto out_del_balloon_wq; } + +#ifdef CONFIG_KVM_FREE_PAGE_HINTING + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) + enable_hinting(vb); +#endif virtio_device_ready(vdev); if (towards_target(vb)) @@ -950,6 +1015,10 @@ static void virtballoon_remove(struct virtio_device *vdev) cancel_work_sync(&vb->update_balloon_size_work); cancel_work_sync(&vb->update_balloon_stats_work); +#ifdef CONFIG_KVM_FREE_PAGE_HINTING + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) + disable_hinting(); +#endif if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { cancel_work_sync(&vb->report_free_page_work); destroy_workqueue(vb->balloon_wq); @@ -1009,6 +1078,7 @@ static unsigned int features[] = { VIRTIO_BALLOON_F_MUST_TELL_HOST, VIRTIO_BALLOON_F_STATS_VQ, VIRTIO_BALLOON_F_DEFLATE_ON_OOM, + VIRTIO_BALLOON_F_HINTING, VIRTIO_BALLOON_F_FREE_PAGE_HINT, VIRTIO_BALLOON_F_PAGE_POISON, }; diff --git a/include/linux/page_hinting.h b/include/linux/page_hinting.h index d554a2581826..a32af8851081 100644 --- a/include/linux/page_hinting.h +++ b/include/linux/page_hinting.h @@ -11,6 +11,8 @@ #define HINTING_THRESHOLD 128 #define FREE_PAGE_HINTING_MIN_ORDER (MAX_ORDER - 1) +extern void *balloon_ptr; + void guest_free_page_enqueue(struct page *page, int order); void guest_free_page_try_hinting(void); extern int __isolate_free_page(struct page *page, unsigned int order); @@ -18,3 +20,5 @@ extern void __free_one_page(struct page *page, unsigned long pfn, struct zone *zone, unsigned int order, int migratetype); void release_buddy_pages(void *obj_to_free, int entries); +extern int (*request_hypercall)(void *balloon_ptr, + void *hinting_req, int entries); diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h index a1966cd7b677..a7e909d77447 100644 --- a/include/uapi/linux/virtio_balloon.h +++ b/include/uapi/linux/virtio_balloon.h @@ -29,6 +29,7 @@ #include <linux/virtio_types.h> #include <linux/virtio_ids.h> #include <linux/virtio_config.h> +#include <linux/page_hinting.h> /* The feature bitmap for virtio balloon */ #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */ @@ -36,6 +37,7 @@ #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ #define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */ #define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */ +#define VIRTIO_BALLOON_F_HINTING 5 /* Page hinting virtqueue */ /* Size of a PFN in the balloon interface. */ #define VIRTIO_BALLOON_PFN_SHIFT 12 @@ -108,4 +110,10 @@ struct virtio_balloon_stat { __virtio64 val; } __attribute__((packed)); +#ifdef CONFIG_KVM_FREE_PAGE_HINTING +struct virtio_balloon_hint_req { + __virtio64 phys_addr; + __virtio64 count; +}; +#endif #endif /* _LINUX_VIRTIO_BALLOON_H */ diff --git a/virt/kvm/page_hinting.c b/virt/kvm/page_hinting.c index 9885b372b5a9..eb0c0ddfe990 100644 --- a/virt/kvm/page_hinting.c +++ b/virt/kvm/page_hinting.c @@ -31,11 +31,16 @@ struct guest_isolated_pages { unsigned int order; }; -void release_buddy_pages(void *obj_to_free, int entries) +int (*request_hypercall)(void *balloon_ptr, void *hinting_req, int entries); +EXPORT_SYMBOL(request_hypercall); +void *balloon_ptr; +EXPORT_SYMBOL(balloon_ptr); + +void release_buddy_pages(void *hinting_req, int entries) { int i = 0; int mt = 0; - struct guest_isolated_pages *isolated_pages_obj = obj_to_free; + struct guest_isolated_pages *isolated_pages_obj = hinting_req; while (i < entries) { struct page *page = pfn_to_page(isolated_pages_obj[i].pfn); @@ -51,7 +56,14 @@ void release_buddy_pages(void *obj_to_free, int entries) void guest_free_page_report(struct guest_isolated_pages *isolated_pages_obj, int entries) { - release_buddy_pages(isolated_pages_obj, entries); + int err = 0; + + if (balloon_ptr) { + err = request_hypercall(balloon_ptr, isolated_pages_obj, + entries); + if (err) + release_buddy_pages(isolated_pages_obj, entries); + } } static int sort_zonenum(const void *a1, const void *b1)
This patch enables the kernel to report the isolated pages to the host via virtio balloon driver. In order to do so a new virtuqeue (hinting_vq) is added to the virtio balloon driver. As the host responds back after freeing the pages, all the isolated pages are returned back to the buddy via __free_one_page(). Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com> --- drivers/virtio/virtio_balloon.c | 72 ++++++++++++++++++++++++++++- include/linux/page_hinting.h | 4 ++ include/uapi/linux/virtio_balloon.h | 8 ++++ virt/kvm/page_hinting.c | 18 ++++++-- 4 files changed, 98 insertions(+), 4 deletions(-)